Humic acids are amphiphilic species whose behavior in aqueous solution suggests that they form pseudomicellesÐaggregates akin to the micelles familiar from synthetic surfactant chemistry. It is thought that humic pseudomicelles can be formed by both intramolecular coiling and intermolecular association, depending on the molecular weight, structural characteristics, and polydispersity of the hum...

We report development of a novel parameter for quantifying the amount of humic and fulvic acids per unit surface area in a particular soil. This quantity, the "humic coverage index" (HCI), provides a measurement of the relative spatial extents and/or thicknesses of the humic/fulvic overlayers in different soils, and, therefore, can be used in modeling various soils' behavior in sequestration pr...

An understanding of the chemistry and reactions of humic acids and related substances is crucial to an understanding of the nature and properties of soils. A comprehensible structural representation of humic substances is presented and the simplified model is used to illustrate: (i) the way in which stable humus is formed from lignin; (ii) forms of organic N in soils; (iii) the interaction of h...

The humic substances including humic acid (HA) and fulvic acids (FAs) extracted from a refuse compost were investigated the average conditional concentration quotients of the complexes formed by the reaction of heavy metals with the humic substances. The characteristics of these humic substances were previously investigated by a related study. The concentrations of the free ions of Pb, Cu, Cd, ...

Mobile and potentially mobile forms of heavy metals are probably one of the most important toxic hazards in the environment. Besides pH, which is a factor influencing the mobility/availability of heavy metals to the greatest extent, the content and mainly the quality of soil organic matter play a very important role in the evaluation of heavy metal behaviour in the environment. The fraction of ...

Radiocarbon dating of Late deposits has shown that erosion of old organic materials and their redeposition in younger sediments ages that are too old. Also, the humid climate and leaching pedogenic environment of much of Tasmania translocation humic acids down profile through porous sediments. The humic acids may then be perched by impermeable clay or may be adsorbed/ absorbed by older clay and...

Increasingly, products containing humic substances are appearing in the turf industry market claiming to reduce water and fertilizer use by increasing soil moisture and nutrient availability. Humic acid is the most common humic substance that has been studied, but results have been highly variable (Cooper et al.; 1998).The response of humic acid is difficult to interpret due to confounding effe...

A strain of Pewicillizi?tz freqzientans was successfully employed for partial degradation and characterization of humic acids. Salicyl alcohol and salicylalclehyde were detected i n culture filtrates of the fungus ~rtilizing humates under reduced oxygen tension. The enzyme systems iiivolved in the degradation of humic acids were adaptive. The humate-adapted lnyceliirln was capable of metabolizi...

In the current research, the effects of some organic fertilizers as fulvic and humic acids on the vegetative growth of pistachio seedlings in a semi-hydroponic culture containing Fe-EDDHA (as a synthetic fertilizer) and FeSO4 (as an inorganic fertilizer) were investigated. The alkalinity is recognized as a main problem in pistachio orchards, therefore the pH of nutrient solution was ...